Emergency evacuation slides may be used to exit an aircraft absent a jet way or other means of egress for passengers. The slides may deploy from a door sill on a side of the aircraft, for example. The sill height may vary in response to the presence of deployed landing gear, the contour of terrain, or a water landing, for example. An evacuation slide performs in the various possible deployment conditions with a suitable slide angle regardless of sill height. However, as the sill height varies the slide angle may vary as well. For example, the sill height of a plane without one of its rear landing gear may be greater than the standard sill height of the aircraft with deployed landing gear. A standard length slide deployed from the increased sill height may result in a steeper slide angle than the same slide would have at standard sill height.
Some evacuation slides may include a toe portion that is inflated or deflated to further adjust the slide angle. The inflation or deflation may depend on measuring the sill height. However, sill height measurements may not be accurate, for example, when an aircraft completes a water landing.